U.S. patent application number 17/712458 was filed with the patent office on 2022-07-14 for method and apparatus for shifting boundary of uplink subframe or uplink slot in wireless communication system.
The applicant listed for this patent is LG Electronics Inc.. Invention is credited to Byounghoon KIM, Yunjung YI.
Application Number | 20220225260 17/712458 |
Document ID | / |
Family ID | |
Filed Date | 2022-07-14 |
United States Patent
Application |
20220225260 |
Kind Code |
A1 |
YI; Yunjung ; et
al. |
July 14, 2022 |
METHOD AND APPARATUS FOR SHIFTING BOUNDARY OF UPLINK SUBFRAME OR
UPLINK SLOT IN WIRELESS COMMUNICATION SYSTEM
Abstract
A method and apparatus for shifting boundary of an uplink (UL)
subframe and/or UL slot in a wireless communication system is
provided. A user equipment (UE) receives information on a timing
advance (TA) offset from the network, and shifts the boundary of
the UL subframe and/or the UL slot based on a TA and the TA offset.
The UE transmits a UL signal as a response to a downlink (DL)
signal in the shifted UL subframe and/or UL slot.
Inventors: |
YI; Yunjung; (Seoul, KR)
; KIM; Byounghoon; (Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LG Electronics Inc. |
Seoul |
|
KR |
|
|
Appl. No.: |
17/712458 |
Filed: |
April 4, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16652869 |
Apr 1, 2020 |
11350380 |
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PCT/KR2018/012012 |
Oct 12, 2018 |
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17712458 |
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62571743 |
Oct 12, 2017 |
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International
Class: |
H04W 56/00 20060101
H04W056/00; H04L 5/00 20060101 H04L005/00; H04W 72/04 20060101
H04W072/04; H04W 74/08 20060101 H04W074/08 |
Claims
1. A method performed by a user equipment (UE) in a wireless
communication system, the method comprising: receiving a
synchronization signal/physical broadcast channel block (SSB) from
a network; obtaining a master information block (MIB) in the SSB;
receiving, from the network, a system information block 1 (SIB1)
based on information for a control resource set (CORESET) included
in the MIB; performing an access to a cell related to the network
based on access information included in the SIB1; receiving a
downlink (DL) data from the network; determining an
acknowledgement/negative-acknowledgement (ACK/NACK) transmission
timing as a timing after a predetermined time interval from an end
of a reception of the DL data; based on that a processing time of
the DL data is less than the predetermined time interval minus an
offset, transmitting an ACK/NACK for the DL data to the network by
applying the offset to a timing advance (TA) so that the ACK/NACK
is transmitted at the offset earlier than the ACK/NACK transmission
timing; and transmitting an UL data to the network by applying the
offset to the TA after transmitting the ACK/NACK, wherein the
offset is configured by the network.
2. The method of claim 1, wherein information on the offset is
received via a remaining minimum system information (RMSI).
3. The method of claim 1, wherein the offset is configured per
frequency range or per frequency band.
4. The method of claim 1, wherein the offset is configured in terms
of number of symbols based on a numerology used in a
synchronization signal block (SSB) including synchronization
signals and a physical broadcast channel (PBCH).
5. The method of claim 1, wherein the offset is configured in terms
of number of symbols based on a numerology used in RMSI.
6. The method of claim 1, wherein the offset is configured in terms
of number of symbols based on at least one of a numerology used in
a UL subframe or a UL slot.
7. The method of claim 1, wherein the offset is applied to a
physical random access channel (PRACH) preamble transmission.
8. The method of claim 1, wherein the UE is in communication with
at least one of a mobile device, a network, or autonomous vehicles
other than the UE.
9. A user equipment (UE) in a wireless communication system, the UE
comprising: a memory; a transceiver, and at least one processor,
operably coupled to the memory and the transceiver, configured to:
control the transceiver to receive a synchronization
signal/physical broadcast channel block (SSB) from a network;
obtain a master information block (MIB) in the SSB; control the
transceiver to receive, from the network, a system information
block 1 (SIB1) based on information for a control resource set
(CORESET) included in the MIB; perform an access to a cell related
to the network based on access information included in the SIB1;
control the transceiver to receive a downlink (DL) data from the
network; determine an acknowledgement/negative-acknowledgement
(ACK/NACK) transmission timing as a timing after a predetermined
time interval from an end of a reception of the DL data; based on
that a processing time of the DL data is less than the
predetermined time interval minus an offset, control the
transceiver to transmit an ACK/NACK for the DL data to the network
by applying the offset to a timing advance (TA) so that the
ACK/NACK is transmitted at the offset earlier than the ACK/NACK
transmission timing; and control the transceiver to transmit an
uplink (UL) data to the network by applying the offset to the TA
after transmitting the ACK/NACK, wherein the offset is configured
by the network.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Application No.
16/652,869, filed on Apr. 1, 2020, which is a National Stage
application under 35 U.S.C. .sctn. 371 of International Application
No. PCT/KR2018/012012, filed on Oct. 12, 2018, which claims the
benefit of U.S. Provisional Application No. 62/571,743, filed on
Oct. 12, 2017. The disclosures of the prior applications are
incorporated by reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to wireless communications,
and more particularly, to a method and apparatus for shifting
boundary of uplink subframe and/or uplink slot in a new radio
access technology (RAT) system.
BACKGROUND
[0003] 3rd generation partnership project (3GPP) long-term
evolution (LTE) is a technology for enabling high-speed packet
communications. Many schemes have been proposed for the LTE
objective including those that aim to reduce user and provider
costs, improve service quality, and expand and improve coverage and
system capacity. The 3GPP LTE requires reduced cost per bit,
increased service availability, flexible use of a frequency band, a
simple structure, an open interface, and adequate power consumption
of a terminal as an upper-level requirement.
[0004] Work has started in international telecommunication union
(ITU) and 3GPP to develop requirements and specifications for new
radio (NR) systems. 3GPP has to identify and develop the technology
components needed for successfully standardizing the new RAT timely
satisfying both the urgent market needs, and the more long-term
requirements set forth by the ITU radio communication sector
(ITU-R) international mobile telecommunications (IMT)-2020 process.
Further, the NR should be able to use any spectrum band ranging at
least up to 100 GHz that may be made available for wireless
communications even in a more distant future.
[0005] The NR targets a single technical framework addressing all
usage scenarios, requirements and deployment scenarios including
enhanced mobile broadband (eMBB), massive
machine-type-communications (mMTC), ultra-reliable and low latency
communications (URLLC), etc. The NR shall be inherently forward
compatible.
SUMMARY
[0006] It is generally expected that timing between DL signal and
UL signal will be reduced, specifically for URLLC. For example,
timing between downlink (DL) data and uplink (UL) hybrid automatic
repeat request acknowledgement (HARQ-ACK) or timing between UL
grant and UL data may be reduced, compared to timing in 3GPP
LTE/LTE-A. In order to efficiently support the reduced timing
between DL signal and UL signal in NR, the present invention
discusses details on UL subframe/slot boundary shift.
[0007] In an aspect, a method for shifting boundary of an uplink
(UL) subframe and/or UL slot by a user equipment (UE) in a wireless
communication system is provided. The method includes receiving a
downlink (DL) signal from a network, receiving information on a
timing advance (TA) offset from the network, shifting the boundary
of the UL subframe and/or the UL slot based on a TA and the TA
offset, and transmitting a UL signal as a response to the DL signal
in the UL subframe and/or UL slot.
[0008] In another aspect, a user equipment (UE) in a wireless
communication system is provided. The UE includes a memory, a
transceiver, and a processor, operably coupled to the memory and
the transceiver, that controls the transceiver to receive a
downlink (DL) signal from a network, controls the transceiver to
receive information on a timing advance (TA) offset from the
network, shifts boundary of an uplink (UL) subframe and/or UL slot
based on a TA and the TA offset, and controls the transceiver to
transmit a UL signal as a response to the DL signal in the UL
subframe and/or UL slot.
[0009] In another aspect, a method for receiving an uplink (UL)
signal by a base station (BS) in a wireless communication system is
provided. The method includes transmitting a downlink (DL) signal
to a user equipment (UE), transmitting information on a timing
advance (TA) offset to the UE, and receiving the UL signal as a
response to the DL signal in a UL subframe and/or UL slot which is
shifted based on a TA and the TA offset.
[0010] Reduced timing between DL signal and UL signal in NR can be
efficiently supported.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows an example of a wireless communication system
to which technical features of the present invention can be
applied.
[0012] FIG. 2 shows another example of a wireless communication
system to which technical features of the present invention can be
applied.
[0013] FIG. 3 shows an example of a frame structure to which
technical features of the present invention can be applied.
[0014] FIG. 4 shows another example of a frame structure to which
technical features of the present invention can be applied.
[0015] FIG. 5 shows an example of a resource grid to which
technical features of the present invention can be applied.
[0016] FIG. 6 shows an example of a synchronization channel to
which technical features of the present invention can be
applied.
[0017] FIG. 7 shows an example of a frequency allocation scheme to
which technical features of the present invention can be
applied.
[0018] FIG. 8 shows an example of multiple BWPs to which technical
features of the present invention can be applied.
[0019] FIG. 9 shows an example of UL subframe/slot shift according
to an embodiment of the present invention.
[0020] FIG. 10 shows another example of UL subframe/slot shift
according to an embodiment of the present invention.
[0021] FIG. 11 shows an example of slot structure according to an
embodiment of the present invention.
[0022] FIG. 12 shows an example of applying TA offset according to
an embodiment of the present invention.
[0023] FIG. 13 shows an example of applying TA offset according to
an embodiment of the present invention.
[0024] FIG. 14 shows an example of not applying TA offset. FIG.
14-(a) shows DL portion.
[0025] FIG. 15 shows a method for shifting boundary of UL subframe
and/or UL slot by a UE according to an embodiment of the present
invention.
[0026] FIG. 16 shows a UE to implement an embodiment of the present
invention.
[0027] FIG. 17 shows a method for receiving UL signal by a BS
according to an embodiment of the present invention.
[0028] FIG. 18 shows a BS to implement an embodiment of the present
invention.
DETAILED DESCRIPTION
[0029] The technical features described below may be used by a
communication standard by the 3rd generation partnership project
(3GPP) standardization organization, a communication standard by
the institute of electrical and electronics engineers (IEEE), etc.
For example, the communication standards by the 3GPP
standardization organization include long-term evolution (LTE)
and/or evolution of LTE systems. The evolution of LTE systems
includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G new radio (NR).
The communication standard by the IEEE standardization organization
includes a wireless local area network (WLAN) system such as IEEE
802.11a/b/g/n/ac/ax. The above system uses various multiple access
technologies such as orthogonal frequency division multiple access
(OFDMA) and/or single carrier frequency division multiple access
(SC-FDMA) for downlink (DL) and/or uplink (DL). For example, only
OFDMA may be used for DL and only SC-FDMA may be used for UL.
Alternatively, OFDMA and SC-FDMA may be used for DL and/or UL.
[0030] FIG. 1 shows an example of a wireless communication system
to which technical features of the present invention can be
applied. Specifically, FIG. 1 shows a system architecture based on
an evolved-UMTS terrestrial radio access network (E-UTRAN). The
aforementioned LTE is a part of an evolved-UTMS (e-UMTS) using the
E-UTRAN.
[0031] Referring to FIG. 1, the wireless communication system
includes one or more user equipment (UE; 10), an E-UTRAN and an
evolved packet core (EPC). The UE 10 refers to a communication
equipment carried by a user. The UE 10 may be fixed or mobile. The
UE 10 may be referred to as another terminology, such as a mobile
station (MS), a user terminal (UT), a subscriber station (SS), a
wireless device, etc.
[0032] The E-UTRAN consists of one or more base station (BS) 20.
The BS 20 provides the E-UTRA user plane and control plane protocol
terminations towards the UE 10. The BS 20 is generally a fixed
station that communicates with the UE 10. The BS 20 hosts the
functions, such as inter-cell radio resource management (RRM),
radio bearer (RB) control, connection mobility control, radio
admission control, measurement configuration/provision, dynamic
resource allocation (scheduler), etc. The BS may be referred to as
another terminology, such as an evolved NodeB (eNB), a base
transceiver system (BTS), an access point (AP), etc.
[0033] A downlink (DL) denotes communication from the BS 20 to the
UE 10. An uplink (UL) denotes communication from the UE 10 to the
BS 20. A sidelink (SL) denotes communication between the UEs 10. In
the DL, a transmitter may be a part of the BS 20, and a receiver
may be a part of the UE 10. In the UL, the transmitter may be a
part of the UE 10, and the receiver may be a part of the BS 20. In
the SL, the transmitter and receiver may be a part of the UE
10.
[0034] The EPC includes a mobility management entity (MME), a
serving gateway (S-GW) and a packet data network (PDN) gateway
(P-GW). The MME hosts the functions, such as non-access stratum
(NAS) security, idle state mobility handling, evolved packet system
(EPS) bearer control, etc. The S-GW hosts the functions, such as
mobility anchoring, etc.
[0035] The S-GW is a gateway having an E-UTRAN as an endpoint. For
convenience, MME/S-GW 30 will be referred to herein simply as a
"gateway," but it is understood that this entity includes both the
MME and S-GW. The P-GW hosts the functions, such as UE Internet
protocol (IP) address allocation, packet filtering, etc. The P-GW
is a gateway having a PDN as an endpoint. The P-GW is connected to
an external network.
[0036] The UE 10 is connected to the BS 20 by means of the Uu
interface. The UEs 10 are interconnected with each other by means
of the PC5 interface. The BSs 20 are interconnected with each other
by means of the X2 interface. The BSs 20 are also connected by
means of the S1 interface to the EPC, more specifically to the MME
by means of the S1-MME interface and to the S-GW by means of the
S1-U interface. The S1 interface supports a many-to-many relation
between MMES/S-GWs and BSs.
[0037] FIG. 2 shows another example of a wireless communication
system to which technical features of the present invention can be
applied. Specifically, FIG. 2 shows a system architecture based on
a 5G new radio access technology (NR) system. The entity used in
the 5G NR system (hereinafter, simply referred to as "NR") may
absorb some or all of the functions of the entities introduced in
FIG. 1 (e.g. eNB, MME, S-GW). The entity used in the NR system may
be identified by the name "NG" for distinction from the LTE.
[0038] Referring to FIG. 2, the wireless communication system
includes one or more UE 11, a next-generation RAN (NG-RAN) and a
5th generation core network (5GC). The NG-RAN consists of at least
one NG-RAN node. The NG-RAN node is an entity corresponding to the
BS 20 shown in FIG. 1. The NG-RAN node consists of at least one gNB
21 and/or at least one ng-eNB 22. The gNB 21 provides NR user plane
and control plane protocol terminations towards the UE 11. The
ng-eNB 22 provides E-UTRA user plane and control plane protocol
terminations towards the UE 11.
[0039] The 5GC includes an access and mobility management function
(AMF), a user plane function (UPF) and a session management
function (SMF). The AMF hosts the functions, such as NAS security,
idle state mobility handling, etc. The AMF is an entity including
the functions of the conventional MME. The UPF hosts the functions,
such as mobility anchoring, protocol data unit (PDU) handling. The
UPF an entity including the functions of the conventional S-GW. The
SMF hosts the functions, such as UE IP address allocation, PDU
session control.
[0040] The gNBs and ng-eNBs are interconnected with each other by
means of the Xn interface. The gNBs and ng-eNBs are also connected
by means of the NG interfaces to the 5GC, more specifically to the
AMF by means of the NG-C interface and to the UPF by means of the
NG-U interface.
[0041] A structure of a radio frame in NR is described. In
LTE/LTE-A, one radio frame consists of 10 subframes, and one
subframe consists of 2 slots. A length of one subframe may be 1 ms,
and a length of one slot may be 0.5 ms. Time for transmitting one
transport block by higher layer to physical layer (generally over
one subframe) is defined as a transmission time interval (TTI). A
TTI may be the minimum unit of scheduling.
[0042] Unlike LTE/LTE-A, NR supports various numerologies, and
accordingly, the structure of the radio frame may be varied. NR
supports multiple subcarrier spacings in frequency domain. Table 1
shows multiple numerologies supported in NR. Each numerology may be
identified by index .mu..
TABLE-US-00001 TABLE 1 Subcarrier Supported for Supported for .mu.
spacing (kHz) Cyclic prefix data synchronization 0 15 Normal Yes
Yes 1 30 Normal Yes Yes 2 60 Normal, Extended Yes No 3 120 Normal
Yes Yes 4 240 Normal No Yes
[0043] Referring to Table 1, a subcarrier spacing may be set to any
one of 15, 30, 60, 120, and 240 kHz, which is identified by index
.mu.. However, subcarrier spacings shown in Table 1 are merely
exemplary, and specific subcarrier spacings may be changed.
Therefore, each subcarrier spacing (e.g. .mu.=0, 1 . . . 4) may be
represented as a first subcarrier spacing, a second subcarrier
spacing . . . Nth subcarrier spacing.
[0044] Referring to Table 1, transmission of user data (e.g.
physical uplink shared channel (PUSCH), physical downlink shared
channel (PDSCH)) may not be supported depending on the subcarrier
spacing. That is, transmission of user data may not be supported
only in at least one specific subcarrier spacing (e.g. 240
kHz).
[0045] In addition, referring to Table 1, a synchronization channel
(e.g. a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), a physical broadcast channel (PBCH))
may not be supported depending on the subcarrier spacing. That is,
the synchronization channel may not be supported only in at least
one specific subcarrier spacing (e.g. 60 kHz).
[0046] In NR, a number of slots and a number of symbols included in
one radio frame/subframe may be different according to various
numerologies, i.e. various subcarrier spacings. Table 2 shows an
example of a number of OFDM symbols per slot, slots per radio
frame, and slots per subframe for normal cyclic prefix (CP).
TABLE-US-00002 TABLE 2 Number of symbols Number of slots Number of
slots .mu. per slot per radio frame per subframe 0 14 10 1 1 14 20
2 2 14 40 4 3 14 80 8 4 14 160 16
[0047] Referring to Table 2, when a first numerology corresponding
to .mu.=0 is applied, one radio frame includes 10 subframes, one
subframe corresponds to one slot, and one slot consists of 14
symbols. In the present specification, a symbol refers to a signal
transmitted during a specific time interval. For example, a symbol
may refer to a signal generated by OFDM processing. That is, a
symbol in the present specification may refer to an OFDM/OFDMA
symbol, or SC-FDMA symbol, etc. A CP may be located between each
symbol.
[0048] FIG. 3 shows an example of a frame structure to which
technical features of the present invention can be applied. In FIG.
3, a subcarrier spacing is 15 kHz, which corresponds to .mu.=0.
[0049] FIG. 4 shows another example of a frame structure to which
technical features of the present invention can be applied. In FIG.
4, a subcarrier spacing is 30 kHz, which corresponds to .mu.=1.
[0050] Meanwhile, a frequency division duplex (FDD) and/or a time
division duplex (TDD) may be applied to a wireless communication
system to which an embodiment of the present invention is applied.
When TDD is applied, in LTE/LTE-A, UL subframes and DL subframes
are allocated in units of subframes.
[0051] In NR, symbols in a slot may be classified as a DL symbol
(denoted by D), a flexible symbol (denoted by X), and a UL symbol
(denoted by U). In a slot in a DL frame, the UE shall assume that
DL transmissions only occur in DL symbols or flexible symbols. In a
slot in an UL frame, the UE shall only transmit in UL symbols or
flexible symbols.
[0052] Table 3 shows an example of a slot format which is
identified by a corresponding format index. The contents of the
Table 3 may be commonly applied to a specific cell, or may be
commonly applied to adjacent cells, or may be applied individually
or differently to each UE.
TABLE-US-00003 TABLE 3 For- Symbol number in a slot mat 0 1 2 3 4 5
6 7 8 9 10 11 12 13 0 D D D D D D D D D D D D D D 1 U U U U U U U U
U U U U U U 2 X X X X X X X X X X X X X X 3 D D D D D D D D D D D D
D X . . .
[0053] For convenience of explanation, Table 3 shows only a part of
the slot format actually defined in NR. The specific allocation
scheme may be changed or added.
[0054] The UE may receive a slot format configuration via a higher
layer signaling (i.e. radio resource control (RRC) signaling). Or,
the UE may receive a slot format configuration via downlink control
information (DCI) which is received on PDCCH. Or, the UE may
receive a slot format configuration via combination of higher layer
signaling and DCI.
[0055] FIG. 5 shows an example of a resource grid to which
technical features of the present invention can be applied. An
example shown in FIG. 5 is a time-frequency resource grid used in
NR. An example shown in FIG. 5 may be applied to UL and/or DL.
Referring to FIG. 5, multiple slots are included within one
subframe on the time domain. Specifically, when expressed according
to the value of ".mu.", "142.mu." symbols may be expressed in the
resource grid. Also, one resource block (RB) may occupy 12
consecutive subcarriers. One RB may be referred to as a physical
resource block (PRB), and 12 resource elements (REs) may be
included in each PRB. The number of allocatable RBs may be
determined based on a minimum value and a maximum value. The number
of allocatable RBs may be configured individually according to the
numerology (".mu."). The number of allocatable RBs may be
configured to the same value for UL and DL, or may be configured to
different values for UL and DL.
[0056] A cell search scheme in NR is described. The UE may perform
cell search in order to acquire time and/or frequency
synchronization with a cell and to acquire a cell identifier (ID).
Synchronization channels such as PSS, SSS, and PBCH may be used for
cell search.
[0057] FIG. 6 shows an example of a synchronization channel to
which technical features of the present invention can be applied.
Referring to FIG. 6, the PSS and SSS may include one symbol and 127
subcarriers. The PBCH may include 3 symbols and 240
subcarriers.
[0058] The PSS is used for synchronization signal/PBCH block (SSB)
symbol timing acquisition. The PSS indicates 3 hypotheses for cell
ID identification. The SSS is used for cell ID identification. The
SSS indicates 336 hypotheses. Consequently, 1008 physical layer
cell IDs may be configured by the PSS and the SSS.
[0059] The SSB block may be repeatedly transmitted according to a
predetermined pattern within the 5ms window. For example, when L
SSB blocks are transmitted, all of SSB #1 through SSB #L may
contain the same information, but may be transmitted through beams
in different directions. That is, quasi co-located (QCL)
relationship may not be applied to the SSB blocks within the 5 ms
window. The beams used to receive the SSB block may be used in
subsequent operations between the UE and the network (e.g. random
access operations). The SSB block may be repeated by a specific
period. The repetition period may be configured individually
according to the numerology.
[0060] Referring to FIG. 6, the PBCH has a bandwidth of 20 RBs for
the 2nd/4th symbols and 8 RBs for the 3rd symbol. The PBCH includes
a demodulation reference signal (DM-RS) for decoding the PBCH. The
frequency domain for the DM-RS is determined according to the cell
ID. Unlike LTE/LTE-A, since a cell-specific reference signal (CRS)
is not defined in NR, a special DM-RS is defined for decoding the
PBCH (i.e. PBCH-DMRS). The PBCH-DMRS may contain information
indicating an SSB index.
[0061] The PBCH performs various functions. For example, the PBCH
may perform a function of broadcasting a master information block
(MIB). System information (SI) is divided into a minimum SI and
other SI. The minimum SI may be divided into MIB and system
information block type-1 (SIB1). The minimum SI excluding the MIB
may be referred to as a remaining minimum SI (RMSI). That is, the
RMSI may refer to the SIB 1.
[0062] The MIB includes information necessary for decoding SIB 1.
For example, the MIB may include information on a subcarrier
spacing applied to SIM (and MSG 2/4 used in the random access
procedure, other SI), information on a frequency offset between the
SSB block and the subsequently transmitted RB, information on a
bandwidth of the PDCCH/SIB, and information for decoding the PDCCH
(e.g. information on search-space/control resource set
(CORESET)/DM-RS, etc., which will be described later). The MIB may
be periodically transmitted, and the same information may be
repeatedly transmitted during 80ms time interval. The SIB1 may be
repeatedly transmitted through the PDSCH. The SIM includes control
information for initial access of the UE and information for
decoding another SIB.
[0063] PDCCH decoding in NR is described. The search space for the
PDCCH corresponds to an area in which the UE performs blind
decoding on the PDCCH. In LTE/LTE-A, the search space for the PDCCH
is divided into a common search space (CSS) and a UE-specific
search space (USS). The size of each search space and/or the size
of a control channel element (CCE) included in the PDCCH are
determined according to the PDCCH format.
[0064] In NR, a resource-element group (REG) and a CCE for the
PDCCH are defined. In NR, the concept of CORESET is defined.
Specifically, one REG corresponds to 12 REs, i.e. one RB
transmitted through one OFDM symbol. Each REG includes a DM-RS. One
CCE includes a plurality of REGs (e.g. 6 REGs). The PDCCH may be
transmitted through a resource consisting of 1, 2, 4, 8, or 16
CCEs. The number of CCEs may be determined according to the
aggregation level. That is, one CCE when the aggregation level is
1, 2 CCEs when the aggregation level is 2, 4 CCEs when the
aggregation level is 4, 8 CCEs when the aggregation level is 8, 16
CCEs when the aggregation level is 16, may be included in the PDCCH
for a specific UE.
[0065] The CORESET may be defined on 1/2/3 OFDM symbols and
multiple RBs. In LTE/LTE-A, the number of symbols used for the
PDCCH is defined by a physical control format indicator channel
(PCFICH). However, the PCFICH is not used in NR. Instead, the
number of symbols used for the CORESET may be defined by the RRC
message (and/or PBCH/SIB1). Also, in LTE/LTE-A, since the frequency
bandwidth of the PDCCH is the same as the entire system bandwidth,
so there is no signaling regarding the frequency bandwidth of the
PDCCH. In NR, the frequency domain of the CORESET may be defined by
the RRC message (and/or PBCH/SIB1) in a unit of RB.
[0066] In NR, the search space for the PDCCH is divided into CSS
and USS. Since the USS may be indicated by the RRC message, an RRC
connection may be required for the UE to decode the USS. The USS
may include control information for PDSCH decoding assigned to the
UE.
[0067] Since the PDCCH needs to be decoded even when the RRC
configuration is not completed, CSS should also be defined. For
example, CSS may be defined when a PDCCH for decoding a PDSCH that
conveys SIB1 is configured or when a PDCCH for receiving MSG 2/4 is
configured in a random access procedure. Like LTE/LTE-A, in NR, the
PDCCH may be scrambled by a radio network temporary identifier
(RNTI) for a specific purpose.
[0068] A resource allocation scheme in NR is described. In NR, a
specific number (e.g. up to 4) of bandwidth parts (BWPs) may be
defined. A BWP (or carrier BWP) is a set of consecutive PRBs, and
may be represented by a consecutive subsets of common RBs (CRBs).
Each RB in the CRB may be represented by CRB1, CRB2, etc.,
beginning with CRB0.
[0069] FIG. 7 shows an example of a frequency allocation scheme to
which technical features of the present invention can be applied.
Referring to FIG. 7, multiple BWPs may be defined in the CRB grid.
A reference point of the CRB grid (which may be referred to as a
common reference point, a starting point, etc.) is referred to as
so-called "point A" in
[0070] NR. The point A is indicated by the RMSI (i.e. SIB1).
Specifically, the frequency offset between the frequency band in
which the SSB block is transmitted and the point A may be indicated
through the RMSI. The point A corresponds to the center frequency
of the CRB0. Further, the point A may be a point at which the
variable "k" indicating the frequency band of the RE is set to zero
in NR. The multiple BWPs shown in FIG. 7 is configured to one cell
(e.g. primary cell (PCell)). A plurality of BWPs may be configured
for each cell individually or commonly.
[0071] Referring to FIG. 7, each BWP may be defined by a size and
starting point from CRB0. For example, the first BWP, i.e. BWP #0,
may be defined by a starting point through an offset from CRB0, and
a size of the BWP #0 may be determined through the size for BWP
#0.
[0072] A specific number (e.g., up to four) of BWPs may be
configured for the UE. At a specific time point, only a specific
number (e.g. one) of BWPs may be active per cell. The number of
configurable BWPs or the number of activated BWPs may be configured
commonly or individually for UL and DL. The UE can receive PDSCH,
PDCCH and/or channel state information (CSI) RS only on the active
DL BWP. Also, the UE can transmit PUSCH and/or physical uplink
control channel (PUCCH) only on the active UL BWP.
[0073] FIG. 8 shows an example of multiple BWPs to which technical
features of the present invention can be applied. Referring to FIG.
8, 3 BWPs may be configured. The first BWP may span 40 MHz band,
and a subcarrier spacing of 15 kHz may be applied. The second BWP
may span 10 MHz band, and a subcarrier spacing of 15 kHz may be
applied. The third BWP may span 20 MHz band and a subcarrier
spacing of 60 kHz may be applied. The UE may configure at least one
BWP among the 3 BWPs as an active BWP, and may perform UL and/or DL
data communication via the active BWP.
[0074] A time resource may be indicated in a manner that indicates
a time difference/offset based on a transmission time point of a
PDCCH allocating DL or UL resources. For example, the start point
of the PDSCH/PUSCH corresponding to the PDCCH and the number of
symbols occupied by the PDSCH/PUSCH may be indicated.
[0075] Carrier aggregation (CA) is described. Like LTE/LTE-A, CA
can be supported in NR. That is, it is possible to aggregate
continuous or discontinuous component carriers (CCs) to increase
the bandwidth and consequently increase the bit rate. Each CC may
correspond to a (serving) cell, and each CC/cell may be divided
into a primary serving cell (PSC)/primary CC (PCC) or a secondary
serving cell (SSC)/secondary CC (SCC).
[0076] Hereinafter, a method for shifting boundary of UL subframe
and/or UL slot according to embodiments of the present invention is
described. The present invention proposes NR frame structure to
support various use case with potential lower latency
operation.
[0077] For the present invention, the followings are basically
assumed. [0078] For enhanced mobile broadband (eMBB) use case (or,
data rate and/or transport block size (TBS) is greater than X),
basic minimum timing for acknowledgement/non-acknowledgment
(ACK/NACK) transmission may be n+k, where n is the subframe/slot
index of end of DL data transmission. That is, when DL data
transmission ends at subframe/slot n, ACK/NACK transmission starts
at subframe/slot n+k. Furthermore, basic minimum timing for UL data
transmission may be n+k, where n is the subframe/slot index of end
of UL grant transmission. That is, when UL grant transmission ends
at subframe/slot n, UL data transmission starts at subframe/slot
n+k.
[0079] Generally, for eMBB use case, basic minimum timing for UL
signal transmission may be n+k, where n is the subframe/slot index
of end of corresponding DL signal transmission. For example, k may
be 2 or 3.
[0080] For ultra-reliable and low latency communications (URLLC)
use case (or, data rate and/or TBS is lower than X but larger than
Y), basic minimum timing for ACK/NACK transmission may be n+k1,
where n is the subframe/slot index of end of DL data transmission.
That is, when DL data transmission ends at subframe/slot n,
ACK/NACK transmission starts at subframe/slot n+k1. Furthermore,
basic minimum timing for UL data transmission may be n+k1, where n
is the subframe/slot index of end of UL grant transmission. That
is, when UL grant transmission ends at subframe/slot n, UL data
transmission starts at subframe/slot n+k1. Generally, for URLLC use
case, basic minimum timing for UL signal transmission may be n+k1,
where n is the subframe/slot index of end of corresponding DL
signal transmission. For example, k1 may be 1.
[0081] For massive machine-type-communications (mMTC) and/or
internet-of-things (IoT) use case (or, data rate and/or TBS is
lower than Y), basic minimum timing for ACK/NACK transmission may
be n+k2, where n is the subframe/slot index of end of DL data
transmission. That is, when DL data transmission ends at
subframe/slot n, ACK/NACK transmission starts at subframe/slot
n+k2. Furthermore, basic minimum timing for UL data transmission
may be n+k2, where n is the subframe/slot index of end of UL grant
transmission. That is, when UL grant transmission ends at
subframe/slot n, UL data transmission starts at subframe/slot n+k2.
Generally, for mMTC and/or IoT use case, basic minimum timing for
UL signal transmission may be n+k2, where n is the subframe/slot
index of end of corresponding DL signal transmission. For example,
k2 may be 12.
[0082] If overall latency to prepare ACK/NACK transmission
(including control/data decoding and timing advance (TA)) is less
than k (or k1 or k2)-delta, UL subframe/slot boundary may be
shifted based on TA offset. The TA offset may be equal to delta. A
value of the TA offset may be positive, which means that the UL
subframe/slot boundary may be shifted backwardly (i.e. same
direction with TA). Or, a value of the TA offset may be negative,
which means that the UL subframe/slot boundary may be shifted
forwardly (i.e. opposite direction with TA). By shifting UL
subframe/slot boundary based on the TA offset, actual latency
between DL data transmission to ACK/NACK transmission may be set to
k-delta (or k1-delta or k2-delta).
[0083] FIG. 9 shows an example of UL subframe/slot shift according
to an embodiment of the present invention. FIG. 9-(a) shows DL
portion. FIG. 9-(b) shows UL portion in which timing of UL
transmission is shifted by TA according to the prior art. FIG.
9-(c) shows UL portion in which timing of UL transmission is
further shifted by the TA offset according to the present
invention.
[0084] By shifting UL subframe/slot boundary based on the TA
offset, the overall latency for ACK/NACK transmission delay and
PUSCH delay can be reduced. The shifting of UL subframe/slot
boundary may be done per UE-specific manner. If the network
supports full duplex radio (FDR), the shifting of UL subframe/slot
boundary may be easy. Or, the shifting of UL subframe/slot boundary
may be done per cell-common manner, e.g. based on overall UE
capability.
[0085] FIG. 10 shows another example of UL subframe/slot shift
according to an embodiment of the present invention. After shifting
UL subframe/slot boundary based on the TA offset, the UE may be
able to further adjust size of resource unit depending on scheduled
data. For example, when the size of resource unit becomes smaller
than subframe/slot--TA (i.e. DL data and ACK/NACK signal can belong
to the same subframe), the UE may adjust the size of its resource
unit. FIG. 10-(a) shows DL portion. FIG. 10-(b) shows UL portion in
which timing of UL transmission is further shifted by the TA offset
according to the present invention. Referring to FIG. 10-(b), the
size of resource unit is adjusted based on the scheduled data. For
example, by reducing data scheduling size, the overall processing
latency can be reduced, and size of the resource unit can be
smaller than subframe/slot size--TA. In this case, a UE may be
allowed to transmit ACK/NACK signal in early timing at the middle
of UL subframe/slot. In this case, UL subframe/slot for ACK/NACK
transmission may end earlier than regular subframe/slot boundary.
For PUSCH, processing time can be reduced with smaller size
transmission or shorter transmission of PUSCH. In this case, the
size of resource unit can be smaller than subframe/slot size--TA.
The PUSCH may be transmitted in early timing at the middle of UL
subframe/slot. The UL subframe/slot for PUSCH transmission may end
earlier than regular subframe/slot boundary.
[0086] As mentioned above, multiple process or multiple overlapped
resource units can be supported, which may complicate the
specification.
[0087] Meanwhile, it important to support high peak data rate as
well as low latency. Accordingly, the followings may be further
considered.
[0088] (1) UL subframe/slot boundary shift where ACK/NACK
transmission can occur in the middle of UL subframe/slot, which may
allow fast turn-around by the network to minimize round trip time
(RTT)
[0089] (2) Aggregation of slot and/or mini-slot
[0090] In shifting UL subframe/slot boundary, the following options
may be considered.
[0091] (1) Configuring TA offset value in RMSI
[0092] TA offset value may be configured in RMSI in terms of
symbols based on numerology used in SS block. Or, TA offset value
may be configured in RMSI in terms of symbols based on numerology
used in RSMI. Or, TA offset value may be configured in RMSI in
terms of symbols with a numerology used for subframe/slot duration,
particularly for UL transmission.
[0093] (2) Configuring fixed TA offset value which is applied to
each TA value regardless of configuration
[0094] The fixed TA offset value may be determined per frequency
range or frequency band. Whether the fixed TA offset value is
applied or not may be indicated by 1 bit in RMSI.
[0095] If this is used, the TA offset value may also be applied to
PRACH transmission. In other words, for the PRACH transmission, a
UE may apply the fixed TA offset as TA (assuming TA value=fixed TA
offset+0). After TA is configured, a UE may transmit PRACH preamble
at t0- TA-fixed TA offset. The fixed TA offset value may be defined
as a constant number which may be different per frequency band or
frequency range. The fixed TA offset value may be configured in
terms of symbols based on numerology used in SS block. Or, the
fixed TA offset value offset value may be configured in terms of
symbols based on numerology used in RSMI. Or, the fixed TA offset
value may be configured in terms of symbols with a numerology used
for subframe/slot duration, particularly for UL transmission.
[0096] (3) Configuring TA offset value in TA value
[0097] In this case, there may be a gap between PRACH transmission
and PUSCH transmission by the TA offset for UEs sharing the same
TA. In this sense, for PRACH reception, the network may require
resource for TAmax (supported by the PRACH formats, or max
propagation delay)+PRACH resource duration+TA offset.
[0098] FIG. 11 shows an example of slot structure according to an
embodiment of the present invention. Referring to FIG. 11, one
PRACH slot may affect two PUSCH slots even with low TA values. To
utilize resources, the network may schedule first short PUSCH/PUCCH
in the first PUCCH/PUSCH slot over first few symbols, and second
short PUSCH/PUCCH in the second PUCCH/PUSCH slot over last few
symbols. This may restrict the scheduling of PUSCH/PUCCH when
slot-based scheduling is used.
[0099] Options for the TA offset value may be as follows.
[0100] (1) N1 (PDSCH to PUCCH HARQ timing in terms of number of
symbols)+M1 (number of symbols used for PUCCH transmission): For
example, N1 is 2 symbols, and M1 is 2 symbols, the TA offset value
may be 4 symbols. In term of realizing the TA offset, particularly
when it is applied to TA, the TA offset may be applied by
increasing slot index by 1.
[0101] FIG. 12 shows an example of applying TA offset according to
an embodiment of the present invention. FIG. 12-(a) shows DL
portion. FIG. 12-(b) shows UL portion in which the TA offset is
applied according to the present invention. For the network, 14
symbols of offset time budget may be allowed for
retransmission.
[0102] Meanwhile, negative value may be considered for the TA
offset. In this case, the TA offset value may be K1+M1, and the UL
subframe/slot boundary can be pushed forwardly.
[0103] (2) In LTE-NR coexistence case, the UL subframe/slot may be
shifted by max
[0104] (N1, P1) or N1+M1+1 (for LTE sounding reference signal (SRS)
protection). P is the number of OFDM symbols not usable to NR due
to LTE PDCCH. As LTE-NR coexistence may always not utilize 1 to 3
symbols, the timing may be used for processing/preparing
HARQ-ACK/PUCCH.
[0105] FIG. 13 shows an example of applying TA offset according to
an embodiment of the present invention. FIG. 13-(a) shows DL
portion. FIG. 13-(b) shows UL portion in which the TA offset is
applied according to the present invention. Referring to FIG.
13-(b), the UL subframe/slot is shifted based on the TA offset.
[0106] FIG. 14 shows an example of not applying TA offset. FIG.
14-(a) shows DL portion. FIG. 14-(b) shows UL portion in which the
TA offset is not applied. Referring to FIG. 14-(b), to utilize
partial subframe structure to achieve low latency, the number of
OFDM symbols usable for UE is very limited. That is, the overall
usable DL resources may decrease significantly.
[0107] In summary, the followings may impact the specification.
[0108] (1) The TA offset may be realized by only by positive TA
(i.e. pull UL subframe/slot by TA+offset). In this case, to allow
same-slot PUCCH transmission related to PDSCH, subframe/slot index
for UL subframe/slot may be increased by 1. Otherwise, in FDD, the
minimum subframe/slot index where PUCCH can be transmitted related
to PDSCH at subframe/slot n is slot n+1 (i.e. K1=1). In this sense,
self-slot scheduling framework may not be usable if the TA offset
is realized by only by positive TA. To utilize resources wasted by
PRACH transmission due to unalignment between different
subframe/slot boundaries, partial PUSCH transmissions may still be
necessary.
[0109] (2) The TA offset is realized by negative TA (i.e. push UL
slot by TA+offset). For example, the TA offset value may be -4
symbols. In this case, the UE needs to be indicated with TA offset
either by RMSI or higher layer signaling. In this case, if
signaling is done by RMSI, PRACH may also apply the TA offset, and
PRACH preamble may be transmitted in UL subframe/slot after
applying the TA offset.
[0110] (3) Half-duplex FDD UEs: By shifting UL subframe/slot, UL
may start in the middle of DL in some cases, which anyway occurs
due to TA. In this case, partial UL data may be scheduled depending
on cases. As long as flexible duration (including starting time) is
indicated by scheduling, this may be easily addressed.
[0111] FIG. 15 shows a method for shifting boundary of UL subframe
and/or UL slot by a UE according to an embodiment of the present
invention. The present invention described above for UE side may be
applied to this embodiment.
[0112] In step S1500, the UE receives DL signal from a network.
[0113] In step S1510, the UE receives information on a TA offset
from the network.
[0114] The TA offset may be a negative value. Or, the TA offset may
be positive value.
[0115] The information on the TA offset may be received via RMSI.
Or, the TA offset may be fixed. In this case, the TA offset may be
configured per frequency range or per frequency band.
[0116] The TA offset may be configured in terms of number of
symbols based on a numerology used in a synchronization SSB. Or,
the TA offset may be configured in terms of number of symbols based
on a numerology used in RMSI. Or, the TA offset may be configured
in terms of number of symbols based on a numerology used in the UL
subframe and/or the UL slot.
[0117] In step S1520, the UE shifts the boundary of the UL subframe
and/or the UL slot based on a TA and the TA offset.
[0118] In step S1530, the UE transmits a UL signal as a response to
the DL signal in the UL subframe and/or UL slot.
[0119] The DL signal may be DL data, and the UL signal may be
ACK/NACK signal of the DL data. Or, the DL signal is a UL grant
scheduling PUSCH, and the UL signal may be UL data transmitted via
the PUSCH. Furthermore, the TA offset may be applied to PRACH
preamble transmission.
[0120] According to embodiment of the present invention shown in
FIG. 15, by shifting UL subframe/slot based on the TA offset in
addition to TA, low latency required by NR can be achieved.
Especially, when the value of the TA offset is negative, i.e. UL
subframe/slot is pushed forwardly, self-subframe/slot scheduling
can be supported efficiently. Consequently, reduced timing between
DL signal and UL signal in NR can be efficiently supported.
[0121] FIG. 16 shows a UE to implement an embodiment of the present
invention. The present invention described above for UE side may be
applied to this embodiment.
[0122] A UE 1600 includes a processor 1610, a memory 1620 and a
transceiver 1630. The processor 1610 may be configured to implement
proposed functions, procedures and/or methods described in this
description. Layers of the radio interface protocol may be
implemented in the processor 1610. Specifically, the processor 1610
controls the transceiver 1630 to receive a DL signal from a
network, controls the transceiver 1630 to receive information on TA
offset from the network, shifts boundary of UL subframe and/or UL
slot based on a TA and the TA offset, and controls the transceiver
1630 to transmit a UL signal as a response to the DL signal in the
UL subframe and/or UL slot.
[0123] The TA offset may be a negative value. Or, the TA offset may
be positive value.
[0124] The information on the TA offset may be received via RMSI.
Or, the TA offset may be fixed. In this case, the TA offset may be
configured per frequency range or per frequency band.
[0125] The TA offset may be configured in terms of number of
symbols based on a numerology used in a synchronization SSB. Or,
the TA offset may be configured in terms of number of symbols based
on a numerology used in RMSI. Or, the TA offset may be configured
in terms of number of symbols based on a numerology used in the UL
subframe and/or the UL slot.
[0126] The DL signal may be DL data, and the UL signal may be
ACK/NACK signal of the DL data. Or, the DL signal is a UL grant
scheduling PUSCH, and the UL signal may be UL data transmitted via
the PUSCH. Furthermore, the TA offset may be applied to PRACH
preamble transmission.
[0127] The memory 1620 is operatively coupled with the processor
1610 and stores a variety of information to operate the processor
1610. The transceiver 1630 is operatively coupled with the
processor 1610, and transmits and/or receives a radio signal.
[0128] The processor 1610 may include application-specific
integrated circuit (ASIC), other chipset, logic circuit and/or data
processing device. The memory 1620 may include read-only memory
(ROM), random access memory (RAM), flash memory, memory card,
storage medium and/or other storage device. The transceiver 1630
may include baseband circuitry to process radio frequency signals.
When the embodiments are implemented in software, the techniques
described herein can be implemented with modules (e.g., procedures,
functions, and so on) that perform the functions described herein.
The modules can be stored in memory 1620 and executed by processor
1610. The memory 1620 can be implemented within the processor 1610
or external to the processor 1610 in which case those can be
communicatively coupled to the processor 1610 via various means as
is known in the art.
[0129] According to embodiment of the present invention shown in
FIG. 16, by shifting UL subframe/slot based on the TA offset in
addition to TA, low latency required by NR can be achieved.
Especially, when the value of the TA offset is negative, i.e. UL
subframe/slot is pushed forwardly, self-subframe/slot scheduling
can be supported efficiently. Consequently, reduced timing between
DL signal and UL signal in NR can be efficiently supported.
[0130] FIG. 17 shows a method for receiving UL signal by a BS
according to an embodiment of the present invention. The present
invention described above for BS side may be applied to this
embodiment.
[0131] In step S1700, the BS transmits DL signal to a UE.
[0132] In step S1710, the BS transmits information on a TA offset
to the UE.
[0133] The TA offset may be a negative value. Or, the TA offset may
be positive value.
[0134] The information on the TA offset may be transmitted via
RMSI. Or, the TA offset may be fixed. In this case, the TA offset
may be configured per frequency range or per frequency band.
[0135] The TA offset may be configured in terms of number of
symbols based on a numerology used in a synchronization SSB. Or,
the TA offset may be configured in terms of number of symbols based
on a numerology used in RMSI. Or, the TA offset may be configured
in terms of number of symbols based on a numerology used in the UL
subframe and/or the UL slot.
[0136] In step S1720, the BS receives the UL signal as a response
to the DL signal in a UL subframe and/or UL slot which is shifted
based on a TA and the TA offset.
[0137] The DL signal may be DL data, and the UL signal may be
ACK/NACK signal of the DL data. Or, the DL signal is a UL grant
scheduling PUSCH, and the UL signal may be UL data transmitted via
the PUSCH. Furthermore, the TA offset may be applied to PRACH
preamble transmission.
[0138] According to embodiment of the present invention shown in
FIG. 17, the information on the TA offset can be provided to the
UE. By shifting UL subframe/slot based on the TA offset in addition
to TA, low latency required by NR can be achieved. Especially, when
the value of the TA offset is negative, i.e. UL subframe/slot is
pushed forwardly, self-subframe/slot scheduling can be supported
efficiently. Consequently, reduced timing between DL signal and UL
signal in NR can be efficiently supported.
[0139] FIG. 18 shows a BS to implement an embodiment of the present
invention. The present invention described above for BS side may be
applied to this embodiment.
[0140] ABS 1800 includes a processor 1810, a memory 1820 and a
transceiver 1830. The processor 1810 may be configured to implement
proposed functions, procedures and/or methods described in this
description. Layers of the radio interface protocol may be
implemented in the processor 1810. Specifically, the processor 1810
controls the transceiver 1830 to transmit DL signal to a UE,
controls the transceiver 1830 to transmit information on a TA
offset to the UE, and controls the transceiver 1830 to receive the
UL signal as a response to the DL signal in a UL subframe and/or UL
slot which is shifted based on a TA and the TA offset.
[0141] The TA offset may be a negative value. Or, the TA offset may
be positive value.
[0142] The information on the TA offset may be transmitted via
RMSI. Or, the TA offset may be fixed. In this case, the TA offset
may be configured per frequency range or per frequency band.
[0143] The TA offset may be configured in terms of number of
symbols based on a numerology used in a synchronization SSB. Or,
the TA offset may be configured in terms of number of symbols based
on a numerology used in RMSI. Or, the TA offset may be configured
in terms of number of symbols based on a numerology used in the UL
subframe and/or the UL slot.
[0144] The DL signal may be DL data, and the UL signal may be
ACK/NACK signal of the DL data. Or, the DL signal is a UL grant
scheduling PUSCH, and the UL signal may be UL data transmitted via
the PUSCH. Furthermore, the TA offset may be applied to PRACH
preamble transmission.
[0145] The memory 1820 is operatively coupled with the processor
1810 and stores a variety of information to operate the processor
1810. The transceiver 1830 is operatively coupled with the
processor 1810, and transmits and/or receives a radio signal.
[0146] The processor 1810 may include ASIC, other chipset, logic
circuit and/or data processing device. The memory 1820 may include
ROM, RAM, flash memory, memory card, storage medium and/or other
storage device. The transceiver 1830 may include baseband circuitry
to process radio frequency signals. When the embodiments are
implemented in software, the techniques described herein can be
implemented with modules (e.g., procedures, functions, and so on)
that perform the functions described herein. The modules can be
stored in memory 1820 and executed by processor 1810. The memory
1820 can be implemented within the processor 1810 or external to
the processor 1810 in which case those can be communicatively
coupled to the processor 1810 via various means as is known in the
art.
[0147] According to embodiment of the present invention shown in
FIG. 18, the information on the TA offset can be provided to the
UE. By shifting UL subframe/slot based on the TA offset in addition
to TA, low latency required by NR can be achieved. Especially, when
the value of the TA offset is negative, i.e. UL subframe/slot is
pushed forwardly, self-subframe/slot scheduling can be supported
efficiently. Consequently, reduced timing between DL signal and UL
signal in NR can be efficiently supported.
[0148] In view of the exemplary systems described herein,
methodologies that may be implemented in accordance with the
disclosed subject matter have been described with reference to
several flow diagrams. While for purposed of simplicity, the
methodologies are shown and described as a series of steps or
blocks, it is to be understood and appreciated that the claimed
subject matter is not limited by the order of the steps or blocks,
as some steps may occur in different orders or concurrently with
other steps from what is depicted and described herein. Moreover,
one skilled in the art would understand that the steps illustrated
in the flow diagram are not exclusive and other steps may be
included or one or more of the steps in the example flow diagram
may be deleted without affecting the scope of the present
disclosure.
* * * * *